Over the past two decades, the incidence of preterm births has increased dramatically. Technological advances in the medical and health sciences have increased the survivability of these preterm infants. The increase in survival, however, has been accompanied by an increase in the incidence of long-term complications associated with premature births such as cerebral palsy (CP), with approximately 10% of preterm infants developing CP. Early diagnosis of CP and other motor abnormalities may enable clinicians to implement early interventions and provide an improved quality of life. Diagnosis is usually made between several months and 2 years of age.
Attempts have been made to develop techniques to be able to detect movement patterns predictive of neurological dysfunction such as CP. One conventional tool for diagnosis of CP is the physician's neurological exam. This exam focuses on the infant's reflexes but places little importance on spontaneous movements. It has been found however that spontaneous movements have a higher predictive value for the development of cerebral palsy compared to reflexive movements. As a result, early diagnosis of CP is often unreliable.
Another tool for diagnosis of CP is the so-called General Movements Assessment (GMA), a technique focused on an infant's spontaneous movements. The GMA is an observational assessment that judges the quality of infant movements and identifies key movements which are markers of neurological dysfunction. General Movements (GMs) of the infant are defined as movements involving the entire body of the infant. Specifically, GMs are a distinct movement pattern carried out spontaneously without external stimulation and seen in fetuses of nine (9) weeks gestational age until about twenty-one (21) weeks post-term. In normal infants, these movements are elegant, smooth and variable in sequence, intensity and speed with a clear beginning and end. The GMA identifies cramped synchronized general movements as one type of abnormal movement. These movements are rigid in nature with the infant's limbs moving in synchrony. The presence of cramped synchronized movements has been shown to have a high predictive value for the development of cerebral palsy.
These conventional approaches to analyze infant movement involve directly observing or videotaping subjects for variable periods of time and then qualitatively analyzing their movements using validated movement scales. One problem with video/direct observation is observer fatigue. One study focusing on natural patterns of physical activity in 6-8 year old children indicated that with a 3-second observation protocol, a typical observer needs a substantial break after about 20 minutes. Moreover, attempting to quantify activity of four (4) limbs in a preterm infant by direct observation is a challenging task, even for the most adept observer. In addition, the clinician must have extensive training in order to accurately carry out these techniques. The time commitment for appropriate training is not always feasible for the neonatal physician or occupational therapist.